[llvm] r284855 - [StripGCRelocates] New pass to remove gc.relocates added by RS4GC
Anna Thomas via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 21 11:43:16 PDT 2016
Author: annat
Date: Fri Oct 21 13:43:16 2016
New Revision: 284855
URL: http://llvm.org/viewvc/llvm-project?rev=284855&view=rev
Log:
[StripGCRelocates] New pass to remove gc.relocates added by RS4GC
Summary:
Utility pass to remove gc.relocates created by rewrite statepoints for GC.
With respect to safepoint verification, the IR generated would be incorrect, and cannot run
as such.
This would be a single transformation on the final optimized IR.
The benefit of the pass is for easy analysis when the IRs are 'polluted' by too
many gc.relocates.
Added tests.
test run: All RS4GC tests with -verify option. Local downstream tests on large
IR files. This also works when the pointer being gc.relocated is another
gc.relocate.
Reviewers: sanjoy, reames
Subscribers: beanz, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D25096
Added:
llvm/trunk/lib/Transforms/Utils/StripGCRelocates.cpp
llvm/trunk/test/Transforms/Util/strip-gc-relocates.ll
Modified:
llvm/trunk/include/llvm/InitializePasses.h
llvm/trunk/include/llvm/Transforms/Scalar.h
llvm/trunk/lib/Transforms/Utils/CMakeLists.txt
llvm/trunk/lib/Transforms/Utils/Utils.cpp
Modified: llvm/trunk/include/llvm/InitializePasses.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/InitializePasses.h?rev=284855&r1=284854&r2=284855&view=diff
==============================================================================
--- llvm/trunk/include/llvm/InitializePasses.h (original)
+++ llvm/trunk/include/llvm/InitializePasses.h Fri Oct 21 13:43:16 2016
@@ -295,6 +295,7 @@ void initializeRegionOnlyViewerPass(Pass
void initializeRegionPrinterPass(PassRegistry&);
void initializeRegionViewerPass(PassRegistry&);
void initializeRegisterCoalescerPass(PassRegistry&);
+void initializeStripGCRelocatesPass(PassRegistry&);
void initializeRenameIndependentSubregsPass(PassRegistry&);
void initializeResetMachineFunctionPass(PassRegistry &);
void initializeReversePostOrderFunctionAttrsLegacyPassPass(PassRegistry&);
Modified: llvm/trunk/include/llvm/Transforms/Scalar.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar.h?rev=284855&r1=284854&r2=284855&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Scalar.h (original)
+++ llvm/trunk/include/llvm/Transforms/Scalar.h Fri Oct 21 13:43:16 2016
@@ -472,6 +472,13 @@ ModulePass *createRewriteStatepointsForG
//===----------------------------------------------------------------------===//
//
+// StripGCRelocates - Remove GC relocates that have been inserted by
+// RewriteStatepointsForGC. The resulting IR is incorrect, but this is useful
+// for manual inspection.
+FunctionPass *createStripGCRelocatesPass();
+
+//===----------------------------------------------------------------------===//
+//
// Float2Int - Demote floats to ints where possible.
//
FunctionPass *createFloat2IntPass();
Modified: llvm/trunk/lib/Transforms/Utils/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/CMakeLists.txt?rev=284855&r1=284854&r2=284855&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/CMakeLists.txt (original)
+++ llvm/trunk/lib/Transforms/Utils/CMakeLists.txt Fri Oct 21 13:43:16 2016
@@ -35,6 +35,7 @@ add_llvm_library(LLVMTransformUtils
ModuleUtils.cpp
NameAnonGlobals.cpp
PromoteMemoryToRegister.cpp
+ StripGCRelocates.cpp
SSAUpdater.cpp
SanitizerStats.cpp
SimplifyCFG.cpp
Added: llvm/trunk/lib/Transforms/Utils/StripGCRelocates.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/StripGCRelocates.cpp?rev=284855&view=auto
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/StripGCRelocates.cpp (added)
+++ llvm/trunk/lib/Transforms/Utils/StripGCRelocates.cpp Fri Oct 21 13:43:16 2016
@@ -0,0 +1,80 @@
+//===- StripGCRelocates.cpp - Remove gc.relocates inserted by RewriteStatePoints===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a little utility pass that removes the gc.relocates inserted by
+// RewriteStatepointsForGC. Note that the generated IR is incorrect,
+// but this is useful as a single pass in itself, for analysis of IR, without
+// the GC.relocates. The statepoint and gc.result instrinsics would still be
+// present.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/Function.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Statepoint.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace {
+struct StripGCRelocates : public FunctionPass {
+ static char ID; // Pass identification, replacement for typeid
+ StripGCRelocates() : FunctionPass(ID) {
+ initializeStripGCRelocatesPass(*PassRegistry::getPassRegistry());
+ }
+
+ void getAnalysisUsage(AnalysisUsage &Info) const override {}
+
+ bool runOnFunction(Function &F) override;
+
+};
+char StripGCRelocates::ID = 0;
+}
+
+bool StripGCRelocates::runOnFunction(Function &F) {
+ // Nothing to do for declarations.
+ if (F.isDeclaration())
+ return false;
+ SmallVector<GCRelocateInst *, 20> GCRelocates;
+ // TODO: We currently do not handle gc.relocates that are in landing pads,
+ // i.e. not bound to a single statepoint token.
+ for (Instruction &I : instructions(F)) {
+ if (auto *GCR = dyn_cast<GCRelocateInst>(&I))
+ if (isStatepoint(GCR->getOperand(0)))
+ GCRelocates.push_back(GCR);
+ }
+ // All gc.relocates are bound to a single statepoint token. The order of
+ // visiting gc.relocates for deletion does not matter.
+ for (GCRelocateInst *GCRel : GCRelocates) {
+ Value *OrigPtr = GCRel->getDerivedPtr();
+ Value *ReplaceGCRel = OrigPtr;
+
+ // All gc_relocates are i8 addrspace(1)* typed, we need a bitcast from i8
+ // addrspace(1)* to the type of the OrigPtr, if the are not the same.
+ if (GCRel->getType() != OrigPtr->getType())
+ ReplaceGCRel = new BitCastInst(OrigPtr, GCRel->getType(), "cast", GCRel);
+
+ // Replace all uses of gc.relocate and delete the gc.relocate
+ // There maybe unncessary bitcasts back to the OrigPtr type, an instcombine
+ // pass would clear this up.
+ GCRel->replaceAllUsesWith(ReplaceGCRel);
+ GCRel->eraseFromParent();
+ }
+ return !GCRelocates.empty();
+}
+
+INITIALIZE_PASS(StripGCRelocates, "strip-gc-relocates",
+ "Strip gc.relocates inserted through RewriteStatepointsForGC",
+ true, false)
+FunctionPass *llvm::createStripGCRelocatesPass() {
+ return new StripGCRelocates();
+}
Modified: llvm/trunk/lib/Transforms/Utils/Utils.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/Utils.cpp?rev=284855&r1=284854&r2=284855&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/Utils.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/Utils.cpp Fri Oct 21 13:43:16 2016
@@ -36,6 +36,7 @@ void llvm::initializeTransformUtils(Pass
initializeMetaRenamerPass(Registry);
initializeMemorySSAWrapperPassPass(Registry);
initializeMemorySSAPrinterLegacyPassPass(Registry);
+ initializeStripGCRelocatesPass(Registry);
}
/// LLVMInitializeTransformUtils - C binding for initializeTransformUtilsPasses.
Added: llvm/trunk/test/Transforms/Util/strip-gc-relocates.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Util/strip-gc-relocates.ll?rev=284855&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/Util/strip-gc-relocates.ll (added)
+++ llvm/trunk/test/Transforms/Util/strip-gc-relocates.ll Fri Oct 21 13:43:16 2016
@@ -0,0 +1,120 @@
+; RUN: opt -S -strip-gc-relocates -instcombine < %s | FileCheck %s
+; test utility/debugging pass which removes gc.relocates, inserted by -rewrite-statepoints-for-gc
+declare void @use_obj32(i32 addrspace(1)*) "gc-leaf-function"
+
+declare void @g()
+declare token @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)
+declare i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token, i32, i32) #0
+declare void @do_safepoint()
+
+declare i32 addrspace(1)* @new_instance() #1
+
+
+; Simple case: remove gc.relocate
+define i32 addrspace(1)* @test1(i32 addrspace(1)* %arg) gc "statepoint-example" {
+entry:
+; CHECK-LABEL: test1
+; CHECK: gc.statepoint
+; CHECK-NOT: gc.relocate
+; CHECK: ret i32 addrspace(1)* %arg
+ %statepoint_token = call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @g, i32 0, i32 0, i32 0, i32 1, i32 100, i32 addrspace(1)* %arg)
+ %arg.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %statepoint_token, i32 8, i32 8) ; (%arg, %arg)
+ %arg.relocated.casted = bitcast i8 addrspace(1)* %arg.relocated to i32 addrspace(1)*
+ ret i32 addrspace(1)* %arg.relocated.casted
+}
+
+; Remove gc.relocates in presence of nested relocates.
+define void @test2(i32 addrspace(1)* %base) gc "statepoint-example" {
+entry:
+; CHECK-LABEL: test2
+; CHECK: statepoint
+; CHECK-NOT: gc.relocate
+; CHECK: call void @use_obj32(i32 addrspace(1)* %ptr.gep1)
+; CHECK: call void @use_obj32(i32 addrspace(1)* %ptr.gep1)
+ %ptr.gep = getelementptr i32, i32 addrspace(1)* %base, i32 15
+ %ptr.gep1 = getelementptr i32, i32 addrspace(1)* %ptr.gep, i32 15
+ %statepoint_token = call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0, i32 addrspace(1)* %ptr.gep1, i32 addrspace(1)* %base)
+ %ptr.gep1.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %statepoint_token, i32 8, i32 7) ; (%base, %ptr.gep1)
+ %ptr.gep1.relocated.casted = bitcast i8 addrspace(1)* %ptr.gep1.relocated to i32 addrspace(1)*
+ %base.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %statepoint_token, i32 8, i32 8) ; (%base, %base)
+ %base.relocated.casted = bitcast i8 addrspace(1)* %base.relocated to i32 addrspace(1)*
+ call void @use_obj32(i32 addrspace(1)* %ptr.gep1.relocated.casted)
+ %statepoint_token1 = call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0, i32 addrspace(1)* %ptr.gep1.relocated.casted, i32 addrspace(1)* %base.relocated.casted)
+ %ptr.gep1.relocated2 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %statepoint_token1, i32 8, i32 7) ; (%base.relocated.casted, %ptr.gep1.relocated.casted)
+ %ptr.gep1.relocated2.casted = bitcast i8 addrspace(1)* %ptr.gep1.relocated2 to i32 addrspace(1)*
+ %base.relocated3 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %statepoint_token1, i32 8, i32 8) ; (%base.relocated.casted, %base.relocated.casted)
+ %base.relocated3.casted = bitcast i8 addrspace(1)* %base.relocated3 to i32 addrspace(1)*
+ call void @use_obj32(i32 addrspace(1)* %ptr.gep1.relocated2.casted)
+ ret void
+}
+
+; landing pad gc.relocates removed by instcombine since it has no uses.
+define i32 addrspace(1)* @test3(i32 addrspace(1)* %arg) gc "statepoint-example" personality i32 8 {
+; CHECK-LABEL: test3(
+; CHECK: gc.statepoint
+; CHECK-LABEL: normal_dest:
+; CHECK-NOT: gc.relocate
+; CHECK: ret i32 addrspace(1)* %arg
+; CHECK-LABEL: unwind_dest:
+; CHECK-NOT: gc.relocate
+entry:
+ %statepoint_token = invoke token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @g, i32 0, i32 0, i32 0, i32 1, i32 100, i32 addrspace(1)* %arg)
+ to label %normal_dest unwind label %unwind_dest
+
+normal_dest: ; preds = %entry
+ %arg.relocated1 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %statepoint_token, i32 8, i32 8) ; (%arg, %arg)
+ %arg.relocated1.casted = bitcast i8 addrspace(1)* %arg.relocated1 to i32 addrspace(1)*
+ ret i32 addrspace(1)* %arg.relocated1.casted
+
+unwind_dest: ; preds = %entry
+ %lpad = landingpad token
+ cleanup
+ %arg.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %lpad, i32 8, i32 8) ; (%arg, %arg)
+ %arg.relocated.casted = bitcast i8 addrspace(1)* %arg.relocated to i32 addrspace(1)*
+ resume token undef
+}
+
+; in presence of phi
+define void @test4(i1 %cond) gc "statepoint-example" {
+; CHECK-LABEL: test4
+entry:
+ %base1 = call i32 addrspace(1)* @new_instance()
+ %base2 = call i32 addrspace(1)* @new_instance()
+ br i1 %cond, label %here, label %there
+
+here: ; preds = %entry
+ br label %merge
+
+there: ; preds = %entry
+ br label %merge
+
+merge: ; preds = %there, %here
+; CHECK-LABEL: merge:
+; CHECK-NOT: gc.relocate
+; CHECK: %ptr.gep.remat = getelementptr i32, i32 addrspace(1)* %basephi.base
+ %basephi.base = phi i32 addrspace(1)* [ %base1, %here ], [ %base2, %there ], !is_base_value !0
+ %basephi = phi i32 addrspace(1)* [ %base1, %here ], [ %base2, %there ]
+ %ptr.gep = getelementptr i32, i32 addrspace(1)* %basephi, i32 15
+ %statepoint_token = call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0, i32 addrspace(1)* %basephi.base)
+ %basephi.base.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %statepoint_token, i32 7, i32 7) ; (%basephi.base, %basephi.base)
+ %basephi.base.relocated.casted = bitcast i8 addrspace(1)* %basephi.base.relocated to i32 addrspace(1)*
+ %ptr.gep.remat = getelementptr i32, i32 addrspace(1)* %basephi.base.relocated.casted, i32 15
+ call void @use_obj32(i32 addrspace(1)* %ptr.gep.remat)
+ ret void
+}
+
+; The gc.relocate type is different from %arg, but removing the gc.relocate,
+; needs a bitcast to be added from i32 addrspace(1)* to i8 addrspace(1)*
+define i8 addrspace(1)* @test5(i32 addrspace(1)* %arg) gc "statepoint-example" {
+entry:
+; CHECK-LABEL: test5
+; CHECK: gc.statepoint
+; CHECK-NOT: gc.relocate
+ %statepoint_token = call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @g, i32 0, i32 0, i32 0, i32 1, i32 100, i32 addrspace(1)* %arg)
+ %arg.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %statepoint_token, i32 8, i32 8) ; (%arg, %arg)
+ ret i8 addrspace(1)* %arg.relocated
+}
+
+attributes #0 = { nounwind readonly }
+attributes #1 = { nounwind "gc-leaf-function" }
+!0 = !{}
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